texture workings

include/blt/gfx/texture.h

@@ -0,0 +1,266 @@
+/*
+ *  <Short Description>
+ *  Copyright (C) 2023  Brett Terpstra
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#ifndef BLT_TEXTURE_H
+#define BLT_TEXTURE_H
+
+#ifdef __EMSCRIPTEN__
+
+#else
+
+#endif
+
+namespace blt::gfx
+{
+    class file_texture {
+        private:
+            std::string m_Name;
+            std::string m_Path;
+            int width = 0, height = 0, channels = 0;
+            unsigned char* m_Data = nullptr;
+        public:
+            /**
+             * @param path path to the texture file
+             * @param name reference name for this texture. If empty the texture will use path as its identifier
+             */
+            explicit file_texture(const std::string& path, const std::string& name = ""):
+                    m_Name(name.empty() ? path : name), m_Path(path) {}
+            
+            static file_texture* load(file_texture*& texture) {
+                // we want to load every texture as if it has transparency,
+                // otherwise textures won't be correctly resized and loaded to the gpu
+                constexpr int channel_count = 4;
+                texture->m_Data = stbi_load(
+                        texture->m_Path.c_str(), &texture->width, &texture->height,
+                        &texture->channels, channel_count
+                );
+                texture->channels = channel_count;
+                return texture;
+            }
+            
+            static file_texture* resize(
+                    file_texture* texture, int target_width, int target_height
+                                       ) {
+                if (target_width == texture->width && target_height == texture->height)
+                    return texture;
+                // since we will be replacing the loaded data pointer, is it wise to use the allocator
+                // that matches with what stb image uses, which is malloc, since we unload with stbi_image_free -> (free)
+                auto* output_Data = (unsigned char*) malloc(
+                        target_width * target_height * texture->channels
+                );
+                
+                // resize the texture
+                if (stbir_resize_uint8(
+                        // input
+                        texture->m_Data, texture->width, texture->height, 0,
+                        // output
+                        output_Data, target_width, target_height, 0,
+                        // channels
+                        texture->channels
+                )) {
+                    BLT_WARN("Error resizing block texture image!");
+                }
+                
+                // free up the old data
+                stbi_image_free(texture->m_Data);
+                texture->m_Data = output_Data;
+                texture->width = target_width;
+                texture->height = target_height;
+                
+                return texture;
+            }
+            
+            unsigned char* data() {
+                return m_Data;
+            }
+            
+            [[nodiscard]] int getChannels() const {
+                return channels;
+            }
+            
+            [[nodiscard]] int getWidth() const {
+                return width;
+            }
+            
+            [[nodiscard]] int getHeight() const {
+                return height;
+            }
+            
+            [[nodiscard]] const std::string& getName() {
+                return m_Name;
+            }
+            
+            ~file_texture() {
+                stbi_image_free(m_Data);
+            }
+    };
+    
+    struct gl_texture {
+        protected:
+            unsigned int textureID = 0;
+            GLint textureBindType;
+            GLint textureColorMode;
+            int m_width, m_height;
+            
+            gl_texture(
+                    int width, int height, GLint bind_type = GL_TEXTURE_2D,
+                    GLint color_mode = GL_RGBA
+                      ):
+                    textureBindType(bind_type), textureColorMode(color_mode), m_width(width),
+                    m_height(height) {
+                glGenTextures(1, &textureID);
+            }
+        
+        public:
+            inline void bind() const {
+                glBindTexture(textureBindType, textureID);
+            }
+            
+            inline void unbind() const {
+                glBindTexture(textureBindType, 0);
+            }
+            
+            void setDefaults() const {
+                bind();
+                glTexParameteri(textureBindType, GL_TEXTURE_WRAP_S, GL_REPEAT);
+                glTexParameteri(textureBindType, GL_TEXTURE_WRAP_T, GL_REPEAT);
+                // nearest preserves the pixely look
+                glTexParameteri(textureBindType, GL_TEXTURE_MIN_FILTER, GL_NEAREST_MIPMAP_LINEAR);
+                glTexParameteri(textureBindType, GL_TEXTURE_MAG_FILTER, GL_NEAREST_MIPMAP_LINEAR);
+                // Anisotropy helps preserve textures at oblique angles
+                float a = 0;
+                glGetFloatv(GL_MAX_TEXTURE_MAX_ANISOTROPY_EXT, &a);
+                glTexParameterf(textureBindType, GL_TEXTURE_MAX_ANISOTROPY_EXT, a);
+                unbind();
+            }
+            
+            inline void generateMipmaps() const {
+                // it's a little inefficient binding and unbinding for these small calls, they really should be done in the constructor or data upload
+                bind();
+                glGenerateMipmap(textureBindType);
+                unbind();
+            }
+            
+            [[nodiscard]] inline unsigned int getTextureID() const {
+                return textureID;
+            }
+            
+            virtual ~gl_texture() {
+                glDeleteTextures(1, &textureID);
+            }
+    };
+    
+    struct gl_texture2D : public gl_texture {
+        public:
+            gl_texture2D(int width, int height, GLint colorMode = GL_RGBA):
+                    gl_texture(width, height, GL_TEXTURE_2D, colorMode) {
+                bind();
+                glTexStorage2D(
+                        textureBindType, std::stoi(fp::settings::get("MIPMAP_LEVELS")), colorMode,
+                        width, height
+                );
+            }
+            
+            void upload(
+                    void* data, GLint dataColorMode = GL_RGBA, int level = 0, int x_offset = 0,
+                    int y_offset = 0, int sub_width = -1,
+                    int sub_height = -1
+                       ) const {
+                if (sub_width < 0)
+                    sub_width = m_width;
+                if (sub_height < 0)
+                    sub_height = m_height;
+                bind();
+                glTexSubImage2D(
+                        textureBindType, level, x_offset, y_offset, sub_width, sub_height,
+                        dataColorMode, GL_UNSIGNED_BYTE, data
+                );
+                unbind();
+            }
+            
+            void upload(file_texture* texture) const {
+                upload(texture->data(), texture->getChannels() == 4 ? GL_RGBA : GL_RGB);
+            }
+            
+            /**
+             * Resizes the internal memory for the texture but does NOT resize the texture image stored
+             */
+            inline void resize(int width, int height) {
+                m_width = width;
+                m_height = height;
+                bind();
+                glTexStorage2D(textureBindType, 0, textureColorMode, m_width, m_height);
+                unbind();
+            }
+    };
+    
+    struct gl_texture2D_array : public gl_texture {
+        protected:
+            int m_layers;
+        public:
+            gl_texture2D_array(int width, int height, int layers, GLint colorMode = GL_RGBA8):
+                    gl_texture(width, height, GL_TEXTURE_2D_ARRAY, colorMode), m_layers(layers) {
+                bind();
+                // 6+ mipmaps is about where I stop noticing any difference (size is 4x4 pixels, so that makes sense)
+                glTexStorage3D(textureBindType, 6, colorMode, width, height, layers);
+                BLT_DEBUG("Creating 2D Texture Array with ID: %d", textureID);
+            }
+            
+            void upload(
+                    void* data, int index, GLint dataColorMode = GL_RGBA, int level = 0,
+                    int x_offset = 0, int y_offset = 0, int sub_width = -1,
+                    int sub_height = -1
+                       ) const {
+                if (sub_width < 0)
+                    sub_width = m_width;
+                if (sub_height < 0)
+                    sub_height = m_height;
+                bind();
+                glTexSubImage3D(
+                        textureBindType, level, x_offset, y_offset, index, sub_width, sub_height, 1,
+                        dataColorMode, GL_UNSIGNED_BYTE, data
+                );
+                unbind();
+            }
+    };
+    
+    class gl_buffer_texture : public gl_texture2D {
+        private:
+        
+        public:
+            // make sure a framebuffer is bound before constructing!
+            gl_buffer_texture(
+                    int width, int height, GLint format = GL_RGB32F,
+                    GLint colorAttachment = GL_COLOR_ATTACHMENT0
+                             ): gl_texture2D(width, height, format) {
+                bind();
+                // no mipmaping and no interpolation to position textures!
+                glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+                glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+                //
+                glFramebufferTexture2D(
+                        GL_FRAMEBUFFER, colorAttachment, GL_TEXTURE_2D, this->textureID, 0
+                );
+                
+            }
+        
+        
+    };
+}
+
+#endif //BLT_TEXTURE_H

src/blt/gfx/texture.cpp

@@ -0,0 +1,17 @@
+/*
+ *  <Short Description>
+ *  Copyright (C) 2023  Brett Terpstra
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */